Unless Irish actor Colin Farrell is wearing extensions in this picture - which we can't rule out - this is a scientific study into how much hair it's possible to grow in five years.
Back in 2003, Farrell completely shaved his head so he could play Bullseye in 'Daredevil.' This picture, taken in 2008, shows him doing press duty for 'Pride and Glory.' Was this look all-natural, or did he get some help from a stylist? If we had to guess, we'd say the latter.